Force actuated injection device

ABSTRACT

An injection device for holding and actuating a pre-filled syringe including a barrel holder having an axial passageway adapted to hold the barrel of the pre-filled syringe, a grip movable relative to the barrel holder to move a plunger of the pre-filled syringe, the grip configured to be locked to the barrel holder to prevent axial movement therebetween and unlocked from the barrel holder to permit axial movement therebetween, and a needle guard arranged to retract into the barrel holder in response to force against an injection site to unlock the grip from the barrel holder.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Continuation-in-Part application claims priority from U.S.application Ser. No. 14/601,420 filed Jan. 21, 2015, which claimspriority from U.S. Application No. 61/929,768 filed Jan. 21, 2014, theentirety of which are incorporated by reference herein.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

The present invention relates generally to an injection device forimproving the speed, accuracy, safety and effectiveness of theadministration of an emergency, life-saving injection during ananaphylactic event, and more particularly, to an injection device thatoperates by way of sequential manual actuation, wherein movement of aneedle guard in response to pressure against the injection siteinitiates a hypodermic injection and triggers the release of a plungerfor delivering medication from a reservoir, in one continuous motion.

Anaphylactic reactions are serious and sometimes fatal reactions toallergens, most commonly caused by food, drugs, insect stings, etc.Studies suggest that food allergies are increasing world-wide. Accordingto a study released by the CDC, food allergies increased approximately50% between 1997 and 2011. More than 17 million Europeans have a foodallergy according to the European Academy of Allergy and ClinicalImmunology. The CDC has also reported that food allergies result in morethan 300,000 ambulatory care visits per year among children under theage of 18.

Auto-injectors are universally recommended as first-aid treatment foranaphylaxis. In a World Allergy Organization survey conducted in 2003,auto-injectors containing 0.3 mg of epinephrine were reported to beavailable in 56.4% of countries, and those containing 0.15 mg ofepinephrine were reported to be available in 43.6% of countries.Auto-injectors containing an infant dose were not available in anycountry.

There have been many studies published about the inability ofauto-injectors to effectively deliver epinephrine, particularly inpediatric patients. A first disadvantage of auto injectors is theineffectiveness to deliver the accurate amount of epinephrine during anemergency anaphylaxis. Current epinephrine auto injectors are availablein two standard doses: 0.15 mg and 0.3 mg, with the 0.15 mg dose forpatients 30 kg and under, and the 0.30 mg dose for patients above 30 kg.According to The Journal of Allergy and Clinical Immunology, neither ofthese doses is appropriate for children weighing less than 10 Kg. A 20kg child would have a similar issue in being under dosed with the 0.15mg dose, and overdosed with the 0.30 mg dose. An overdose or under doseduring a life threatening anaphylaxis, especially for a child or patientwith small body mass, could be fatal.

A second disadvantage of auto injectors is the inability to effectivelydeliver the medication intramuscularly using one standard needle length.A study conducted at the Phoenix Children's Hospital found that theneedle on epinephrine auto-injectors is not long enough to reach themuscle in a significant number of children. Another study presentedduring the 2013 Annual Meeting of the American Academy of Allergy,Asthma & Immunology (AAAAI) suggested that delivering epinephrine intothe muscle allows for more rapid absorption and leads to higher bloodlevels than if injected into the overlying fat. Considering the risingobesity rates in children, there is concern that epinephrineauto-injectors will not adequately deliver the medication in overweightchildren who may be experiencing anaphylaxis. Without proper treatment,anaphylaxis can be fatal, therefore it is critical that epinephrine isadministered quickly and effectively.

Additional studies have found that patient groups other than childrenare at risk of not receiving an adequate dose of epinephrine in ananaphylactic emergency. One study published in the American Journal ofEmergency Medicine found that the current epinephrine auto injectorneedle length is inadequate for intramuscular injection, especiallyamong women.

One study conducted at the University of Manitoba assessed absorption ofepinephrine when injected subcutaneously and intramuscularly inchildren. The data showed subcutaneous injections reached the meanmaximum plasma concentration at a range of 5 to 120 minutes. Patientsinjected intramuscularly reached a mean maximum plasma concentration in8+/−2 minutes. This study supports the conclusion that, in children,recommendations for subcutaneous epinephrine injection are based onanecdotal experience, and should be reevaluated in view of the findingof delayed epinephrine absorption when this route is used. This delaymay have important clinical implications during an episode of systemicanaphylaxis. Thus, the intramuscular route of injection is preferable.According to the National Institute of Allergy and Infectious Disease,if epinephrine is not given promptly, rapid decline and death couldoccur within 30 to 60 minutes. These findings clearly illustrate theneed for patients experiencing anaphylactic shock to receive rapidintramuscular injections of epinephrine.

A third disadvantage of auto injectors is the high cost, whichparticularly affects developing nations.

While vial and syringe combinations for epinephrine administration havethe advantage of being economical, they are cumbersome to carry on adaily basis, time-consuming to load and administer, and mostimportantly, open the door to dosage errors. Patients requiringself-administration are typically not capable of loading a syringe andadministering the correct dosage during an anaphylactic event.

Therefore, what is needed is an economical alternative for administeringinjections during an anaphylactic event that overcomes the disadvantagesof prior art injectors.

BRIEF SUMMARY OF THE INVENTION

It is an object of the invention to provide an injection deviceconfigured to deliver an accurate, personalized, rapid injection of acritical care life-saving dosage of epinephrine when speed, dosageaccuracy and proper intramuscular delivery during an anaphylactic eventare critical, particularly in children and other small body masspatients.

It is another object of the invention to provide an injection devicecalibrated to a patient's weight and/or Body Mass Index (BMI) in orderto administer a precise dosage with the most operative needle length toimprove the speed, accuracy, safety and effectiveness of theadministration of a critical care injection such as epinephrine, orother medication.

It is another object of the invention to provide an injection devicethat is cost-effective and easy to use.

It is another object of the invention to provide an injection deviceconfigured to administer an injection in one continuous motion using theenergy from the force of injection, and not stored energy within thedevice.

It is another object of the invention to provide an injection devicethat operates by way of sequential “stages” in one continuous motion toadminister a medical injection from the force of applied pressureagainst the injection site.

It is another object of the invention to provide an injection device inwhich a predetermined amount of pressure against the injection siteinitiates the device to, in sequence, puncture the injection site,penetrate hypodermically to a patient specific depth, and deliver apatient specific dosage from within the reservoir of the device.

It is another object of the invention to provide an injection deviceconfigured to deliver an injection by way of momentum initiated by theretraction or other actuation of the needle guard or like component ofthe device applied by force against the injection site.

It is another object of the invention to provide an injection device foradministering a medicinal injection that operates by utilizing momentumfrom the force of injection to deliver the medication.

To achieve the foregoing and other objects and advantages, in a firstembodiment provided herein is an injection device including a barrelholder having an axial passageway adapted to hold a barrel of apre-filled syringe, a grip slidably disposed over the barrel holder andadapted to engage a plunger of the pre-filled syringe, the gripconfigured to lock to the barrel holder to prevent axial movementtherebetween and unlock from the barrel holder to allow axial movementtherebetween to drive axial movement of the plunger relative to thebarrel, and a needle guard configured to partially retract into thebarrel holder in response to force against an injection site to unlockthe grip from the barrel holder.

In a further aspect, the grip can have a removable cap at one endthereof adapted to engage an end of the plunger, the removable caphaving an opening through a sidewall thereof for allowing the removablecap to slide over the end of the plunger when installing the removablecap on the grip.

In a further aspect, the injection device can have a barrel lock at oneend of the barrel holder configured to lock the barrel to the barrelholder.

In a further aspect, the barrel holder can have a recess at one endthereof adapted to receive a finger flange of the pre-filled syringe,and a rail laterally adjacent the recess, wherein the barrel lock isconfigured to engage the finger flange and is slidable along the rail torotate the finger flange relative to the barrel holder to compress thefinger flange to lock the barrel to the barrel holder.

In a further aspect, the barrel holder can have a window through asidewall thereof for viewing indicia or fluid of the pre-filled syringe.

In a further aspect, the injection device can include grip locksdisposed in openings through sidewalls of the barrel holder, the griplocks arranged to contact the grip to lock the grip to the barrel holderand move out of contact with the grip in response to contact with theneedle guard to unlock the grip from the barrel holder.

In a further aspect, the grip locks can be biased in a direction outwardaway from the barrel holder.

In a further aspect, the injection device can include a biasing memberdisposed between the barrel holder and the needle guard arranged to biasthe needle guard away from the barrel holder.

In a further aspect, the injection device can include a removable coverattached to one end of the grip.

In a further aspect, the needle guard can include a cylindrical bodyhaving a pair of diametrically opposed arms extending axially from oneend of the cylindrical body in a direction of the grip, wherein as theneedle guard retracts into the barrel holder a predetermined distancethe arms urging the grip locks inward out of contact with the grip tounlock the grip from the barrel holder to permit axial movementtherebetween.

In a further aspect, the arms can be guided along elongate channelswithin the barrel holder.

In a further aspect, the injection device is momentum driven in thatforce against the injection site causes the needle guard to retract intothe barrel holder a predetermined distance to unlock the grip from thebarrel holder to allow the grip to move in a direction of the injectionsite to advance the plunger in the barrel to deliver a dosage ofpredetermined medication in one continuous motion.

In a further aspect, the injection device can include a needle depthadjustment mechanism associated with the barrel and including a rotatingdial for adjusting a position of the barrel relative to the barrelholder to adjust needle depth.

According to another embodiment of the invention, the present inventionprovides an injection device for actuating a pre-filled syringeincluding a barrel holder having an axial passageway adapted to hold abarrel of the pre-filled syringe, a grip movable relative to the barrelholder to move a plunger of the pre-filled syringe, the grip configuredto be locked to the barrel holder to prevent axial movement therebetweenand unlocked from the barrel holder to permit axial movementtherebetween, and a needle guard arranged to retract into the barrelholder in response to force against an injection site to unlock the gripfrom the barrel holder.

Embodiments of the invention can include one or more or any combinationof the above features, aspects and configurations.

Additional features, aspects and advantages of the invention will be setforth in the detailed description which follows, and in part will bereadily apparent to those skilled in the art from that description orrecognized by practicing the invention as described herein. It is to beunderstood that both the foregoing general description and the followingdetailed description present various embodiments of the invention, andare intended to provide an overview or framework for understanding thenature and character of the invention as claimed. The accompanyingdrawings are included to provide a further understanding of theinvention, and are incorporated in and constitute a part of thisspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects and advantages of the present invention are betterunderstood when the following detailed description of the invention isread with reference to the accompanying drawings, in which:

FIG. 1 is an isometric view of an injection device according to a firstembodiment of the invention;

FIG. 2 is an exploded view of the device of FIG. 1;

FIG. 3 is an isometric view of the barrel of the device of FIG. 1;

FIG. 4 is a longitudinal sectional view through the barrel of FIG. 3;

FIG. 5 is a cutaway view of the barrel of FIG. 3;

FIG. 6 is an isometric view of the plunger assembly of the device ofFIG. 1;

FIG. 7 is a cutaway view of the plunger assembly of FIG. 6;

FIG. 8 is an exploded view of the plunger assembly of FIG. 6;

FIG. 9 is an isometric view of the needle guard of the device of FIG. 1;

FIG. 10 is an isometric view of the plunger stop of the device of FIG.1;

FIG. 11 is an isometric view of the plunger lock of the device of FIG.1;

FIG. 12 is an isometric view of the removable safety cap of the deviceof FIG. 1;

FIG. 13 is an isometric view of the device of FIG. 1 shown with theplunger lock in the non-operative position;

FIG. 14 is an isometric view of the device of FIG. 13 shown from anotherangle;

FIG. 15 shows a medication vial aligned with the needle guard;

FIG. 16 shows the needle inserted into the vial;

FIG. 17 shows the device of FIG. 1 loaded with a predetermined dosage ofmedication and with the plunger lock in the operative position;

FIG. 18 is a detailed view of the plunger lock;

FIG. 19 is a detailed view of the plunger lock and plunger stopengagement;

FIG. 20 shows the device of FIG. 1 with the needle guard retracted andwith the plunger in the starting position;

FIG. 21 is a detailed view illustrating movement of the needle guardtriggering release of the plunger;

FIG. 22 shows the device of FIG. 1 with the needle guard retracted andthe plunger fully depressed;

FIG. 23 is an isometric view of an injection device according to asecond embodiment of the invention;

FIG. 24 is a longitudinal sectional view through the device of FIG. 23;

FIG. 25 shows the device of FIG. 23 with the safety cap removed;

FIG. 26 shows the device of FIG. 23 with the needle guard partiallyretracted;

FIG. 27 is an exploded view of the device of FIG. 23;

FIG. 28 is another exploded view of the device of FIG. 23;

FIG. 29 is a sectional view through the device of FIG. 23 showing thedevice loaded and ready for use;

FIG. 30 is a sectional view through the device of FIG. 23 showing theneedle guard partially retracted and the plunger locked;

FIG. 31 is a sectional view through the device of FIG. 23 showing theneedle guard fully retracted and the plunger released;

FIG. 32 is an isometric view of an injection device according to a thirdembodiment of the invention;

FIG. 33 shows the device of FIG. 32 with the safety cap removed and theplunger lock in the non-operative position;

FIG. 34 shows the vial aligned with the needle guard;

FIG. 35 shows the needle inserted into the vial;

FIG. 36 shows the device loaded with a predetermined dosage;

FIG. 37 shows the loaded device with the plunger lock in the operativeposition;

FIG. 38 is a detailed view of the plunger lock;

FIG. 39 shows the needle depth setting of the device;

FIG. 40 shows the needle depth adjuster;

FIG. 41 is a detailed view of the needle depth adjuster;

FIG. 42 shows the device of FIG. 32 loaded and set to a predeterminedneedle depth;

FIG. 43 shows the needle guard retracted and the plunger in the startingposition;

FIG. 44 shows the needle guard retracted and the plunger fullydepressed;

FIG. 45 is a sectional view through the device showing plunger release;

FIG. 46 is an exploded view of the device of FIG. 32;

FIG. 47 is an isometric view of the barrel of the device of FIG. 32;

FIG. 48 is a longitudinal sectional view through the barrel;

FIG. 49 is a cutaway view of the barrel of FIG. 47;

FIG. 50 is an isometric view of the plunger assembly of the device ofFIG. 32;

FIG. 51 is a cutaway view through the plunger assembly;

FIG. 52 is an exploded view of the plunger assembly of FIG. 50;

FIG. 53 is an isometric view of the needle guard of the device of FIG.32;

FIG. 54 is an isometric view of the plunger stop of the device of FIG.32;

FIG. 55 is another isometric view of the plunger stop;

FIG. 56 is an isometric view of the plunger lock of the device of FIG.32;

FIG. 57 is an isometric view of an injection device according to afourth embodiment of the invention;

FIG. 58 is a longitudinal sectional view through the device of FIG. 57;

FIG. 59 shows the device of FIG. 57 loaded with a predetermined dosageand ready for use;

FIG. 60 shows the device of FIG. 57 with the needle guard partiallyretracted;

FIG. 61 is an exploded view of the device of FIG. 57;

FIG. 62 is another exploded view of the device of FIG. 57;

FIG. 63 is a sectional view through the device of FIG. 57 showing theneedle guard extended and the plunger assembly locked;

FIG. 64 is a sectional view through the device of FIG. 57 showing theneedle guard partially retracted and the plunger assembly locked;

FIG. 65 is a sectional view through the device of FIG. 57 showing theplunger assembly unlocked;

FIG. 66 is an isometric view of an injection device configured to hold apre-filled syringe;

FIG. 67 is a vertical cross-section through the injection device of FIG.65;

FIG. 68 shows the pre-filled syringe removed from the injection device;

FIG. 69 shows a syringe lock in an unlocked position;

FIG. 70 shows the syringe lock in a locked position;

FIG. 71 shows the needle guard extended thereby concealing the needle;

FIG. 72 shows the needle guard retracted and the plunger fullydepressed;

FIG. 73 is an exploded view of the injection device of FIG. 66; and

FIG. 74 is another exploded view of the injection device of FIG. 66.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings in which exemplary embodiments ofthe invention are shown. However, the invention may be embodied in manydifferent forms and should not be construed as limited to therepresentative embodiments set forth herein. The exemplary embodimentsare provided so that this disclosure will be both thorough and complete,and will fully convey the scope of the invention and enable one ofordinary skill in the art to make, use and practice the invention. Likereference numbers refer to like elements throughout the variousdrawings.

Referring to FIGS. 1-22, a first embodiment of an injection device foradministering a dosage of epinephrine or other critical care injection,referred to generically herein as the “medication,” is shown generallyat reference numeral 100. Although the injection device shown anddescribed herein utilizes a needle for delivering the medication, it isenvisioned and intended that the features and configurations describedherein may be adapted to and implemented with other types of injectiondevices for delivering medication hypodermically.

The injection device 100 generally includes a barrel 102, a plungerassembly 106, and a removable safety cap 158. The barrel defines aninternal reservoir for containing a volume of medication, also referredto herein as the “dosage.” The plunger assembly 106 is axially movablerelative to the barrel 102 in a first direction to load the reservoir,and in the opposing direction to force the medication from thereservoir.

The injection device further includes a hypodermic needle 108 configuredto attach to one end of the barrel, for example by way of a Luer-lock,to deliver the medication intramuscularly, subcutaneously, or anotherroute, and a retractable needle guard 110 for guarding the needle andtriggering the delivery mechanism of the injection device, as describedbelow. The plunger assembly 106 generally includes a grip 128 thataxially overlaps a portion of the barrel 102, and a plunger 112configured to be fixed relative to the grip 128. The plunger 112 may bereceived through one end of the grip 128 by way of a removable cap 130.The cap 130 secures in place over one end of the plunger 112 to fix theinner plunger relative to the outer grip. In use, the grip 128 andplunger 112 move together axially relative to the barrel 102 to load andadminister the medication. A plunger stop 142 is arranged to controlaxial movement of the plunger 112 relative to the barrel 102, and aplunger lock 150 functions to lock the axial position of the plungerassembly 106 relative to the barrel 102, for example, to set the dosage.

The barrel 102 is an elongate, generally cylindrical body defining aninternal passageway therethrough. The hypodermic needle 108 attaches toone end of the barrel 102, and the opposing end of the barrel is open toreceive the internal plunger 112 of the plunger assembly 106. Anairtight seal is provided between one end of the plunger 112 and theinner wall of the barrel reservoir 104 such that the medication isforced from the reservoir through the hypodermic needle as the plungeris axially advanced into the barrel 102, and cannot pass between theplunger 112 and the reservoir wall. The barrel 102 has a generallycylindrical cross-section with diametrically opposed flat sides. Theflat sides may serve to locate indicia 121, for example, volumetricindicia. Volumetric indicia may include, but is not limited to, mL, IU,CC, MG, MCG, etc. Indicia may also be provided in the form of KG, LB,Body Surface Area (BSA), Body Mass Index (BMI), etc.

The barrel 102 defines a lateral flange 114 adjacent the needle end tofacilitate gripping and manipulating the barrel to introduce air intothe reservoir. The barrel 102 defines an elongate annular passage 116for receiving the retracting needle guard 110. The barrel 102 definesdiametrically opposed guide channels 118 for aligning and guiding theneedle guard 110 as the needle guard retracts into the barrel. Anannular chamber 120 surrounds the end of the reservoir 104 opposite theneedle end and receives the plunger stop 142. The end of the reservoiropposite the needle end terminates in an internal cylindrical stem 122having diametrically opposed external rails 124 and optional externalthreading 126 around at least a portion of the circumference thereof,the rails and optional threading functioning, at least in part, to guidethe plunger stop into place 142 and facilitate alignment of the plungerstop with the retracting needle guard 110.

The plunger assembly 106 generally includes the outer grip 128 and theinternal plunger 112. The grip 128 has a cross-section similar to thatof the barrel 102, albeit a larger diameter, such that a portion of thegrip axially overlaps the barrel and rotation therebetween is prevented.The plunger 112 terminates at one end in a seal 117 and at the opposingend in an enlarged head 118 trapped between an annular flange of thegrip 128 and the removable cap 130. The grip 128 defines one or morewindows, with window 132 indicating the dosage and defined along a flatface of the grip corresponding in alignment with the underlyingvolumetric indicia on the barrel. Windows 134 are defined thru anarcuate portion of the grip 128 and are used to accessing and manipulatethe plunger lock therethrough. The grip 128 may define exterior grippingfeatures 136 to facilitate gripping. An enlarged lateral flange 138functions as a palm rest during the injecting motion.

The needle guard 110 is a generally cylindrical body havingdiametrically opposed guide rails 140 extending axially from one endthereof. The needle guard 110 and plunger assembly are calibrated toresist a specific amount of force to actuate the needle guard “upwards”(i.e., in the direction of the barrel). The needle guard 110 “unlocks”the delivery mechanism upon the applied pressure from the injectionsite, which in turn allows the medication to be delivered. The needleguard 110 retracts within the barrel as the hypodermic needle advancesinto the patient. At the same time, the guide rails 140 are guided alongthe guide channels within the barrel. The needle guard 110 retracts asit comes into contact with the injection site from the force of theinjection. The needle guard 110 may have a predetermined length therebyproviding a predetermined amount of linear length between the needleguard end and the needle tip, thus allowing a calibrated amount ofmomentum to be in place for the needle tip to penetrate the patient.Prior to injection, the needle guard 110 also functions to conceal theneedle and prevent accidental sticks. The needle guard 110 alsodesensitizes the injection site just prior to the needle puncturing theskin lessoning/reducing the initial pricking/pinching sensation felt bythe patient. A relatively tight fit may be provided between the barrel102 and the needle guard 110 such that a predetermined force is neededto move the needle guard relative to the barrel. With such a tight fit,the needle guard is not free to move simply by changing the orientationof the tool, but requires that the needle guard either come into contactwith the injection site or is otherwise purposefully handled and moved(e.g., retracted or pulled).

The plunger stop 142, which sits within the annular chamber around thestem, generally includes an annular band 144 having diametricallyopposed arms 146 that extend in the same direction away and outward fromthe band. The band defines inner channels 148 that align with the stemrails to align the plunger stop 142 relative to/on the stem. The arms146 are resiliently deformable and biased radially outward such thatwhen the needle guard 110 is not fully retracted the ends of the armsengage within a slot in the plunger lock to prevent axial movement ofthe plunger relative to the barrel, and are forced radially inward andout of engagement with the plunger lock when the needle guard isretracted, thereby allowing the plunger to move axially relative to thebarrel to deliver the medication.

The plunger lock 150 functions to lock the axial position of the plungerassembly relative to the barrel, for example, to set the dosage. Theplunger lock 150 includes diametrically opposed finger grips 152 thatare accessible through the windows located along the sides of the grip.The plunger lock 150 may be made from a resiliently deformable materialcapable of being compressed radially inward in order to disengage teeth154 from corresponding teeth located on the inner wall of the grip (seeFIG. 18 at 156). The plunger lock 150 installs around the stem of thebarrel, and the arms of the plunger stop rest against the end or ashoulder of the plunger lock 150 when the plunger lock is in theoperative position, thus preventing axial movement between the plungerand barrel. As the arms 146 are urged radially inward in response toforce from the retracting needle guard 110, the arms move out ofengagement with and clear of the plunger lock 150, thereby allowing theplunger assembly to move axially in the direction of the barrel todeliver the medication.

The needle cap 158 is removed before syringe use. The needle cap 158defines an outer cylindrical portion 160 that surrounds at least aportion of the needle guard, and an inner cylindrical needle holder 162that surrounds the hypodermic needle. The needle holder 162 may functionto hold the hypodermic needle during coupling with the Luer-lok of thebarrel.

FIGS. 13-22 detail the sequential steps of readying, loading andadministering an injection utilizing injection device 100. First,referring to FIG. 13, with the safety cap removed, the plunger lock 150is moved to a predetermined starting position at the end of the grip 128opposite the barrel, thereby allowing the plunger assembly to movefreely relative to the barrel. Next, referring to FIG. 14, the usergrips the grip 128, resting the top of the hand firmly against theunderside of the grip flange 138 and placing the thumb against theunderside of the barrel flange in order to push the barrel 102 in thedirection away from the plunger to introduce air into the reservoir.Next, referring to FIG. 15, the user aligns the vial with the needleguard flange. Next, referring to FIG. 16, the user pushes the injectiondevice or vial until the needle penetrates the vial and the “-0-” orequivalent zero dosage shows through the dosage window 132. The plungeris then withdrawn from the barrel 102 to fill the reservoir to thedesired dosage amount that appears through the dosage window 132.

Next, referring to FIG. 17, with the vial removed, the needle guard 110is pulled out to a starting position and the plunger lock is “pinched”to compress the plunger lock radially to slide it into the operative“locked” position against the arms of the plunger stop. FIG. 18 detailsthe plunger lock 150 engaging the teeth 156 on the inner surface of thegrip. FIG. 19 details the plunger lock 150 engagement with the barreland with the arms of the plunger stop.

Next, referring to FIG. 20, to administer the injection, the user gripsthe grip 128 seating the hand against the grip flange 138. The userapplies a downward pressure on the grip and grip flange 138, therebycausing force between the injection site and needle guard 110 until theneedle guard collapses and retracts upward into the barrel 102 apredetermined distance and the needle penetrates the injection site inresponse to forward pressure against the injection site. Referring toFIG. 21, as the needle guard 110 retracts, the needle guard rails 140move into contact with the plunger stop arms 146. As the needle guard110 continues to retract, the contact between the rails 140 and the arms146 urges the arms radially inward, thereby releasing the plunger stopand allowing the plunger to move to complete the injection. Referring toFIG. 22, as part of the continuous injecting motion, the plungercontinuous its “downward” motion to force the medication from thereservoir and out through the needle 108. Thus, needle guard retraction,needle insertion, plunger release, and plunger movement are sequentiallyperformed in one continuous motion from force against the injectionsite, and plunger movement is stayed until the needle is fully insertedinto the patient to a predetermined depth. After the injection iscomplete, the injection device may be discarded or reused aftersterilizing the device and replacing the needle.

Referring to FIGS. 23-31, a second embodiment of an injection device foradministering a dosage of medication is shown generally at referencenumeral 200. Like injection device 100, injection device 200 generallyoperates by way of user force and momentum to sequentially insert theneedle, trigger release of the plunger, and deliver the medication, inone continuous motion. Unlike injection device 100, in which the dosagecan be adjusted, injection device 200 is pre-loaded with a predetermineddosage. The dosage can be customized based on weight, BMI and BSA, amongother factors.

The injection device 200 includes a needle cap 258 removed prior to use.The needle cap 258 includes an inner cylindrical needle holder 259 thatconceals the hypodermic needle 108. The needle cap 258 may be held inplace, for example, by way of interference fit around a portion of thegrip 228. Injection device 200 generally includes a barrel 202 definingan internal reservoir 204 containing a predetermined volume ofmedication, a plunger assembly 206 axially movable relative to thebarrel to force the medication from the reservoir, a hypodermic needle108 for delivering the medication intramuscularly, subcutaneously, orother route, and a retractable needle guard 210 for releasing theplunger assembly 206 to allow axial movement of the plunger relative tothe barrel.

The barrel 202 may be a unitary or multi-piece body. The hypodermicneedle 108 attaches to one end of the barrel 202, and the opposing endof the barrel is open to receive an internal plunger 212 of the plungerassembly 206 therein. An airtight seal is provided between the plunger212 and the reservoir 204 such that the pre-loaded medication is forcedthrough the needle as the plunger moves axially in the direction of thebarrel 202. A portion of the barrel 202 has a generally cylindricalcross-section with diametrically opposed flat sides, which correspond inshape to the overlying grip 228 to prevent rotation therebetween whenaxially overlapped. The end of the reservoir adjacent the needle, i.e.,the interface between the reservoir and needle, may be sealed with afoil or like seal that ruptures in response to the initial plungermovement and/or consequential pressure build-up in the reservoir. Therupture of the seal allows the medication to flow from the reservoir 204to the needle.

In response to predetermined pressure against the injection site, theneedle guard 210 rapidly retracts into the barrel 202. The barrel 202defines an annular, internal space 216 for receiving the cylindricalbody of the retracting needle guard 210, and diametrically opposed guidechannels 218 for receiving and aligning the corresponding guide rails240 extending from the needle guard body. The plunger stop 242positioned around the axially extending stem 222 of the barrel 202includes diametrically opposed arms 246 extending in the direction ofthe top of the grip 228. In use, the arms 246 are resiliently deformableand biased radially outward such that when the needle guard 210 isextended the ends of the arms engage within corresponding slots 260 thruthe grip 228 to prevent axial movement of the plunger 212 relative tothe barrel 202. When the needle guard 210 is retracted into the barrel202 a sufficient distance, the needle guard urges the arms 246 radiallyinward out of engagement with the grip slots 260 such that the rails 240can pass beyond the arms allowing the grip 228 to continue its motion inthe direction of the injection site, thereby allowing the medication tobe delivered. Features 260 facilitate gripping and handling.

Referring to FIGS. 32-56, a third embodiment of an injection device foradministering a dosage of medication is shown generally at referencenumeral 300. Injection device 300 operates much like injection devices100 and 200, with the added functionality of adjustable needle length.It is should be understood that the adjustable needle lengthfunctionality may be added to one or more of injection devices 100 and200 for the added benefit of patient customization, among otheradvantages.

Grip 328 includes a dosage window 332 through which the set dosage isindicated, and a needle depth window 334 through which the needle depthis indicated, for example, in units of millimeters. FIG. 32 shows theinjection device 100 with the needle cap 358 installed, therebyconcealing the underlying needle and preventing contamination. FIG. 33shows the injection device in the “starting position,” with the dosageset to “-0-”, the plunger lock 350 disengaged allowing the plungerassembly 306 to move freely, and with the minimum needle depth set. Vialor ampoule alignment and plunger lock operation work in the same mannerdescribed above with reference to injection device 100.

The needle depth may be adjusted to change the depth of needlepenetration. Depth of penetration is controlled by adjusting the pointat which the needle guard 310 engages the plunger stop 342 to triggerthe release of the plunger 312, and the adjustment is actuated byrotating a dial 370 accessible through the flat face of the grip 328opposite the face including the dosage and needle depth indicationwindows. The dial 370 is part of an assembly also including one or moredial nuts 372 threaded onto the plunger stem 322. The dial 370 and oneor more dial nuts 372 are meshed gears, wherein rotational motion of thedial 370 causes rotational motion of the one or more dial nuts 372. Whenturned, the one or more dial nuts 372 force the plunger stop 342 up ordown the plunger stem 322 depending on the desired needle depth. In theembodiment shown, the dial assembly includes upper and lower dial nuts372 positioned vertically above and below the plunger stop 342, and thedial 370 is held in a meshed arrangement with the dial nuts 372 by wayof a dial holder 374 positioned adjacent a side of the plunger stop 342.With the dosage and needle depth set, the injection device 300 operatesto deliver the dedication similar to injection device 100.

The barrel 302 generally includes the reservoir 304 for holding themedication, the stem 322 for locating the plunger stop 342, and thevarious guides and chambers for locating and guiding the retractableneedle guard 310. Teeth on the stem 322 serve to grip the barrel 302 toprevent the plunger from pulling out of the barrel once the medicationhas been loaded and the plunger lock set to the predetermined dosageamount for the injection. External threads 376 on the stem 322 engagethe internal threading on the one or more dial nuts 372 to adjust theneedle depth in response to rotational movement of the dial 370. Thegrip flange 338 serves as a palm rest during the injecting motion.

The plunger stop 342 includes resilient arms 346 for engaging theplunger lock 350 (see FIG. 56) to prevent the plunger 312 from advancinginto the reservoir 304 until released. Needle depth indicia may belocated on a face of the plunger stop visible through the needle depthwindow 334. A slot is provided on one face of the dial for attaching thedial holder.

Referring to FIGS. 57-65, a fourth embodiment of an injection device foradministering a dosage of epinephrine or other critical care injectionis shown generally at reference numeral 400. Injection device 400generally includes a barrel 402, plunger assembly 404, needle guard 406and removable safety cap 408. As best shown in FIG. 58, the grip 410 andinternal plunger 412 may be integrally formed, and the grip 410 may havea pistol grip shape to facilitate gripping.

The needle guard 406 is biased in the direction concealing thehypodermic needle 414. Optional helical spring 416 may be maintainedbetween the needle guard 406 and the end of the barrel 402, requiring asmall amount of force to overcome the spring force to retract the needleguard into the barrel. In an alternative embodiment, a resistance band422 may be positioned surrounding the end of the barrel between theouter surface of the barrel and inner surface of the needle guard 406.The resistance band resists movement of the needle guard 406 relative tothe barrel 402, requiring a predetermined degree of force to initiateretraction movement of the needle guard into the barrel. The helicalspring 416 may be optionally included to provide smooth movement of theneedle guard 406 relative to the barrel 402 throughout its range ofmovement. In one particular embodiment, both a resistance band andhelical spring may be utilized, with the former resisting initial needleguard movement until a predetermined threshold resistance force isovercome, and the later providing smooth needle guard movementthereafter and biasing force in the direction concealing the needle.

A pair of axially extending spaced arms 418 of the needle guard 406travel along the inner surface of the barrel 402. As the needle guard406 is retracted into the barrel 402, the ends of the arms 418 engage apair of spaced locks 420 to drive them radial inward to unlock theplunger assembly 404 from the barrel, thereby allowing the plunger 412to be axially advanced into the reservoir.

The spaced locks 420 are arranged between the barrel 402 and innersurface of the grip 410 and are spring biased in the direction of thegrip. Each lock 420 is ramped such that continued movement of the arms418 in the direction of the locks causes the locks to be driven radiallyinward out of contact with the grip 410. In the “locked” position, eachlock sits within a recess defined along the inner surface of the grip410. In the “unlocked” position, the locks are driven from theirrespective recesses such that the plunger assembly 404 is free to moverelative to the barrel 402. FIG. 63 shows the needle guard 406 fullyextended and the locks 420 in their locked position. FIG. 64 shows theneedle guard 406 partially retracted into the barrel and with with thearms 418 making initial contact with the locks 420. FIG. 65 shows theneedle guard 406 retracted a sufficient amount such that the locks 420are driven ort urged radially inward and out of contact with the grip410.

Referring to FIGS. 66-74, a device for controlling actuation of apre-filled syringe is shown generally at reference numeral 500. Thedevice 500 generally operates to hold a syringe filled with apredetermined medication, i.e., a pre-filled syringe, and actuate thesyringe to administer the predetermined medication in response topressure against the injection site as discussed above in connectionwith the foregoing embodiments. In other words, the injection device 500is momentum driven in that force against the injection site causes theneedle guard of the device to partially retract into the barrel holder apredetermined distance to unlock the grip from the barrel holder toallow the grip to move in a direction of the injection site to advancethe syringe plunger into the syringe barrel to deliver a dosage of thepredetermined medication in one continuous motion.

The injection device 500 generally includes a barrel holder 502 havingan internal axial passageway adapted to receive/hold a barrel 504 of thepre-filled syringe 506, a grip 508 slidably disposed over the barrelholder and adapted to engage a plunger 510 of the pre-filled syringe,and a needle guard 512 configured to partially retract into the barrelholder in response to force against the injection site to unlock thegrip from the barrel holder. When locked, the grip 508 is fixed relativeto the barrel holder 502 thereby preventing axial movement therebetweenand consequently plunger movement relative to the syringe barrel. Whenunlocked, the grip 508 is able to move relative to the barrel holder 502thereby pushing the plunger 510 in the direction of the barrel 504 todrive the predetermined medication out through the needle 514. FIG. 66shows the injection device 500 locked and with a removable cover 516installed, while FIG. 67 is a vertical sectional view through theinjection device shown with the cover removed and with the grip 508locked relative to the barrel holder 502.

The grip 508 has a removable cap 518 at one end thereof adapted toengage an end of the plunger 510 when installed on the grip. Theremovable cap 518 has an opening 520 through a sidewall 522 thereof forallowing the removable cap to slide over or past the end of the plunger510 when installing the removable cap on the grip 508. As best shown inFIG. 68, the pre-filled syringe 506 is installed into the injectiondevice 500 by first removing the cap 518 from the grip 508, nextinserting the syringe 506 into the injection device, and finallyreplacing the cap 518 by sliding the cap onto the grip 508 from the sideof the grip. The cap 518 and grip 508 can secure together throughslide-lock engagement or equivalent manner of engagement. When the cap518 is installed on the grip 508 the inner face of the end of the capcan directly contact the end of the enlarged head of the plunger.

As best shown in FIGS. 69 and 70, the syringe barrel locks to the barrelholder 502 by way of a lock 524 positioned at one end of the barrelholder configured to lock the syringe barrel relative to the barrelholder. As shown, the finger flange 526 formed at the end of the syringebarrel sits within a recess formed in the end of the barrel holder 502.The lock 524, which slides along a rail 528 laterally adjacent therecess, defines a feature at one end that engages through a surroundingrelationship one wing of the finger flange. More specifically, the lock524 captures the wing of the finger flange between two arms thereof suchthat sliding the lock 524 along the rail 528 causes the finger flange toturn within the recess. The recess can be topped with a flange thatallows the finger flange to pass thereunder when rotated to the lockedposition, thereby compressing the finger flange and locking the syringebarrel relative to the barrel holder. In the locked position, thesyringe barrel is prevented from moving axially or rotationally relativeto the barrel holder. The lock 524 is unlocked by sliding the lock inthe opposite direction along the rail 528.

As best shown in FIG. 66, the injection device 500 can further include awindow 530 through a sidewall thereof for viewing indicia 532 or fluidof the pre-filled syringe installed within the device to ensure properinstallation among other purposes.

Referring to FIGS. 71 and 72, the needle guard 512 partially retractsinto the barrel holder in response to force against the injection site.FIG. 71 shows the needle guard 512 fully extended thereby concealing theneedle. FIG. 72 shows the needle guard 512 partially retracted therebyexposing the needle. As can be seen referring to FIGS. 67, 73 and 74,grip 508 locking relative to the barrel holder 502 is achieved using apair of diametrically opposed grip locks 534 outwardly biased in thedirection away from the barrel holder 502. Biasing can be achieved usinghelical springs 536 or equivalent biasing member positioned inward ofthe grip locks 534. Each grip lock 534 seats within a dedicated openingor recess 538 defined in the sidewall of the barrel holder 502. Whenassembled, the grip locks 534 are biased outward to engage an innersurface of the grip 508 to lock the grip to the barrel holder 504, andare arranged to move out of contact with the grip 508 in response tocontact with the needle guard 512 as the needle guard retracts into thebarrel holder 502.

The needle guard 512 generally includes a cylindrical tubular body 540having a pair of diametrically opposed arms 542 extending axially fromone end of the cylindrical body in a direction of the grip 508. As theneedle guard 512, and particularly the arms 542, retract into the barrelholder 502 a predetermined distance, the arms 542 contact the grip locks534 thereby urging the grip locks inward and out of contact with thegrip 508 to unlock the grip from the barrel holder 502 to permit axialmovement therebetween. The arms 542 can be guided along elongatechannels 544 within the interior of the barrel holder 502. A biasingmember, such as a helical spring 546 can be disposed between one end ofthe barrel holder 502 and the needle guard 512 arranged to bias theneedle guard in the direction away from the barrel holder, therebyrequiring force against the injection site sufficient to overcome thespring force in order to allow the needle guard 512 to retract.

As in the above injection device embodiments, the injection device 500can further include a needle depth adjustment mechanism including aplunger stop, a rotating dial accessible through a face of the grip, andone or more dial nuts adapted to thread on the plunger, the rotatingdial adapted to mesh with the one or more dial nuts such that rotationof the dial rotates the one or more dial nuts to move the plunger stopup or down the plunger.

In any of the foregoing embodiments, the injection device may beincluded in a kit for increasing the effectiveness and safety of aninjection. The kit may include the injection device marked with patientweight indicia, for example from 1-40 Kg for pediatric patients, orother patient characteristic indicia. The kit may further include one ormore of a BMI card to assess a patient's BMI, correlating needles havinga predetermined length to be used with the injection device, and a vialor other medicament container including a predetermined volume tosupport predetermined dosages.

The injection device or kit may be volumetrically predetermined for themedication and targeted patient class and/or patient segment dosagerange. It is contemplated herein that the injection device may be filledby a user to a specific dosage, weight or other measurement, and thedosage stored and “locked” within the reservoir of the injection devicefor later use. The injection device may be pre-filled with themedicament to a predetermined volume to fulfill the administrationrequirements of a specific patient class, weight or other feature, as anexample, pre-filled for a pediatric patient class of 40 Kg or under, orpre-filled for an infant weight class from 1-10 Kg. The injection devicemay be pre-filled with medication corresponding to a specific patientweight class or other patient characteristic dosage or dosage range, andpredetermined needle length. The injection device may be pre-filled witha predetermined volume of medication to fulfill the administrationrequirements of a specific patient class, weight, BMI or other patientcharacteristic, and may also include a patient specific needle or otherhypodermic delivery apparatus with packaging, labeling, color or textthat would assist a user in a quick identification of the most optimalinjection device for a particular patient.

The foregoing description provides embodiments of the invention by wayof example only. It is envisioned that other embodiments may performsimilar functions and/or achieve similar results. Any and all suchequivalent embodiments and examples are within the scope of thisdisclosure.

What is claimed is:
 1. An injection device, comprising: a barrel holderhaving an axial passageway adapted to hold a barrel of a pre-filledsyringe; a grip slidably disposed over the barrel holder and adapted toengage a plunger of the pre-filled syringe, the grip including aremovable cap installable at one end of the grip, the removable capadapted to engage an end of the plunger upon installation of theremovable cap on the grip, and the removable cap including an openingthrough a sidewall thereof allowing the removable cap to slide over theend of the plunger when installing the removable cap on the grip, thegrip configured to lock to the barrel holder to prevent axial movementtherebetween and unlock from the barrel holder to allow axial movementtherebetween to drive axial movement of the plunger relative to thebarrel; a barrel lock at one end of the barrel holder for preventingrelative movement between the barrel holder and the barrel of thepre-filled syringe when installed in the barrel holder, the barrel lockincluding a recess for receiving a finger flange, a rail adjacent therecess, and a lock slidable along the rail into or out of engagementwith the finger flange; and a needle guard configured to partiallyretract into the barrel holder in response to force against an injectionsite to unlock the grip from the barrel holder by urging inward at leastone outwardly biased element engaging the grip.
 2. The injection deviceof claim 1, wherein the barrel holder comprises a window through asidewall thereof for viewing indicia or fluid of the pre-filled syringe.3. The injection device of claim 1, further comprising grip locksdisposed in openings through sidewalls of the barrel holder, the griplocks arranged to contact the grip to lock the grip to the barrel holderand move out of contact with the grip in response to contact with theneedle guard to unlock the grip from the barrel holder.
 4. The injectiondevice of claim 3, wherein the grip locks are biased outward away fromthe barrel holder.
 5. The injection device of claim 3, wherein theneedle guard comprises a cylindrical body having a pair of diametricallyopposed arms extending axially from one end of the cylindrical body in adirection of the grip, as the needle guard retracts into the barrelholder a predetermined distance the arms urging the grip locks inwardout of contact with the grip to unlock the grip from the barrel holderto permit axial movement therebetween.
 6. The injection device of claim5, wherein the arms are guided along elongate channels within the barrelholder.
 7. The injection device of claim 1, further comprising a biasingmember disposed between the barrel holder and the needle guard arrangedto bias the needle guard away from the barrel holder.
 8. The injectiondevice of claim 1, wherein the injection device is momentum driven inthat force against the injection site causes the needle guard to retractinto the barrel holder a predetermined distance to unlock the grip fromthe barrel holder to allow the grip to move in a direction of theinjection site to advance the plunger in the barrel to deliver a dosageof predetermined medication in one continuous motion.
 9. An injectiondevice for actuating a pre-filled syringe, comprising: a barrel holderhaving an axial passageway adapted to hold a barrel of the pre-filledsyringe; a grip movable relative to the barrel holder to move a plungerof the pre-filled syringe, the grip including a removable cap at one endthereof, the removable cap adapted to engage an end of the plunger uponinstallation of the removable cap at the one end of the grip, the gripconfigured to be locked to the barrel holder to prevent axial movementtherebetween and unlocked from the barrel holder to permit axialmovement therebetween; a barrel lock at one end of the barrel holder forpreventing relative movement between the barrel holder and the barrel ofthe pre-filled syringe when installed in the barrel holder, the barrellock including a recess for receiving a finger flange, a rail adjacentthe recess, and a lock slidable along the rail into or out of engagementwith the finger flange; and a needle guard arranged to retract into thebarrel holder in response to force against an injection site to unlockthe grip from the barrel holder by urging inward at least one outwardlybiased element engaging the grip.
 10. The injection device of claim 9,wherein the at least one outwardly biased element is disposed inopenings through sidewalls of the barrel holder, the at least oneoutwardly biased element arranged to contact the grip to lock the gripto the barrel holder and move out of contact with the grip in responseto contact with the needle guard to unlock the grip from the barrelholder, wherein the at least one outwardly biased element is biasedlaterally away from the barrel holder.
 11. The injection device of claim9, further comprising a biasing member disposed between the barrelholder and the needle guard arranged to bias the needle guard away fromthe barrel holder.
 12. The injection device of claim 9, wherein theneedle guard comprises a cylindrical body having a pair of diametricallyopposed arms extending axially from one end thereof in a direction ofthe grip, as the needle guard retracts into the barrel holder apredetermined distance the arms urging the at least one outwardly biasedelement inward out of contact with the grip to unlock the grip from thebarrel holder to permit axial movement therebetween, wherein the armsare guided along elongate channels within the barrel holder.